Separate the whites from the yolks. Proteins vzbit in a lush foam with a pinch of salt. Beat until stable peaks. Beat the yolks with the sugar until the mixture will increase in volume and become whitish. Add the fourth part of the whites and mix. Then pour the sifted flour with the baking powder and lemon juice. Gently stir the remaining whites, stirring with a spatula in the direction from top to bottom. Preheat the oven to 180 degrees. Divide the dough into two bowls. One part will be a little more. In large part, add cocoa, stir gently. Test 2 fill in forms and bake for 20-25 minutes. Check for readiness with a toothpick - it should come out dry from the center. Meanwhile, prepare the cream beat sour cream with sugar to the consistency of a lush light cream. You need to stir them until complete dissolution of sugar crystals. The whisking will depend on the quality and fat content of sour cream. The cream should be light and fluffy, hold shape. If not thickened, add a little corn starch.

The finished cake to get out of shape, separating them with a knife from the walls, cool. Chocolate cake layer cut in half lengthwise, leaving the bottom 1.5-2 cm base. Light biscuit and the rest of the chocolate chopped in small cubes 2-3 cm layer - the base to lubricate sour cream. Sprinkle with nuts and chopped pineapple. Then start assembling the cake: place a layer of slices of sponge cake, brush with sour cream, sprinkle with nuts and pineapple. Repeat until you run out of biscuit and cream. The cake should be in the form of a dome. After all the layers are stacked to cover the remaining sour cream. You can put the cake in the freezer for 20 minutes. Top the cream will seize and the chocolate will harden faster when you decorate. Melt the chocolate in a water bath or in a microwave oven (turn on for a few seconds at a time and stir). Pour melted chocolate on top. Put in the refrigerator to soak at least 4 hours, preferably overnight. BON APPETIT!